Biological pollutants including harmful bacteria and similar microorganisms also known as bioaerosols are pathogenic agents. These airborne microorganisms may also occur naturally and may be found, for instance, in different places wherein humans have contact with animals and/or in low hygiene environmental conditions. The said bioaerosols cause diseases that are acquired by inhaling particles from particular environments. They can also be spread into the air from where they may be transmitted to new hosts. The hosts of said micro-pathogens may develop a variety of serious and painful diseases that may result in the death of the host. Among the vulnerable host victims of these microorganisms are mammals, including humans.
For instance, the disease Psittacosis, caused by Chlamydia psittaci has its source in dried, powdery droppings from infected birds such as parrots and pigeons. Similarly, the Legionnaire's disease is a common form of pneumonia in older or immuno-compromised people and it can be transmitted to humans via the droplets from air-conditioning systems, water storage tanks and other water containing places wherein the bacterium Legionella pneumophila grows. Indeed, these microorganisms are a major cause of respiratory ailments of humans, causing allergies asthma and pathogenic infections of the respiratory tract. The said pathogenic infections may be viral or bacterial. Among important diseases affecting humans, which are transmitted person to person by inhaling airborne particles, may contain viruses that cause sicknesses like chickenpox, influenza, measles, and smallpox. On the other hand, examples of some airborne bacterial diseases transmitted from person to person(s) inhalation are Whooping cough, caused by Bordetella pertussis, Meningitis, caused by Neisseria species, Diphtheria caused by Corynebacterium diphtheriae, Pneumonia caused by Mycoplasma pneumoniae and Streptococcus species and Tuberculosis caused by Mycobacterium tuberculosis. 
Additionally, it is very well known that bioaerosols may be used as biological warfare. These present day issues have become a terrible threat to big cities everywhere in our planet. Indeed, our society is in state of alert regarding potential terrorist attacks that may involve chemical and biological agents. Possible areas that are considered targets are banks, universities, public shopping areas, public transportation centers, hospitals, and entertainment events able to hold hundreds or thousand of people. These targets may be attacked by a simple act of disseminating a highly lethal biological or chemical weapon. Considering bioaerosols' characteristics: low cost, difficult detection and identification, easy dissemination, high contagious potential and the long range effects; biological agents appear to pose the greatest threat as compared with other the various methods of attack. Regardless of the origin, these microorganisms may cause multiple diseases, or medical conditions like allergies and respiratory problems that are easy to transfer to others hosts, establishing a contamination of large communities.
Unfortunately, current methods to detect and identify the said microorganisms require lengthy analysis. By the time the detection and identification of the microorganism is completed, the damage may be very extensive and the recovery extremely expensive and challenging.
The prior art discloses different methods for the detection of bioaerosol particles in gaseous sample wherein the detection system integrates spectroscopic techniques.
For instance, Carpenter et al, U.S. Pat. No. 5,254,861, discloses a system and method for the detection of the said airborne micro bio-particles wherein the particles to be detected are ionized by impacting the said particles with low energy UV radiation followed by the detection of the biological ionized particle with a detector. Carpenter's detector comprises a pair of electrically charged conducting plates placed in a parallel confronting relationship to each other.
Another example, Ho, U.S. Pat. No. 5,701,012, discloses an apparatus and a method for the detection of viable and potentially hazardous biological particles dispersed in an air stream. Ho's method comprises particle's size determination and distinguishes particles as biological from the inert non-biological particles. Ho's method comprises impacting particles with a 340 nm UV laser followed by detecting the UV emission of the particle within the particular wavelength range of approximately 400-540 nm.
Similarly, Grow U.S. Pat. No. 5,866,430, discloses a method for the identification of chemical pollutants and microorganisms. Grow's method relies on Raman spectroscopic techniques. It comprises the preparation of a complex among the analyte and a bioconcentrator, followed by exposing the said complex with a particular radiation in order to produce a Raman scattering spectrum. Detection is complete once the spectrum of the complex is collected and processed by a Raman spectrometer. Notice that the detection system and process is done based upon the complex formed and not directly from the actual specimen.
On the other hand, Stenger et al, U.S. Pat. No. 6,103,534 discloses a method for the detection of bioaerosol that comprises reaction of the bioaerosol with a chemiluminescent reagent; followed by measuring the luminescense of the mixture. Stenger's method requires very sensitive equipment made of very specific materials.
Chang et al, U.S. Pat. No. 6,532,067, discloses a method for the measurement of bioaerosols that comprises measuring size of the particle and the fluorescence spectra of single micrometer sized biological particles. Chang's method uses a light source to induce fluorescence in the UV range, preferably having 266 nm or 351 nm and does not provide a clear substantial determination of the size and velocity of the particle. Chang's velocity determination requires the simultaneous scattering of light by two different wavelengths diode lasers and the fluorescence spectra are measured only for particles falling within preset size parameters. Moreover, in Chang's method the particles are randomly dispersed in the collection and the detection steps. Clearly, the above limitations are serious disadvantages resulting from the pre-selective sensitivity and low selectivity.
More recently, Chang et al, U.S. Pat. No. 6,947,134, discloses a method and instrumentation for measuring fluorescence spectra of individual airborne-particles sampled from ambient air. The instrument performs measurements in real time and determines the size of particles measured is from 1-10 μm in diameter. It uses a Q-switched UV laser operating at wavelength of 266 nm. The main difference among the cited Chang's patents is the incorporation of a Q-switched laser in the UV range in Chang's U.S. Pat. No. 6,947,134.
Thusly, the prior art lacks to disclose in-time bioaerosol detection and accurate characterization methods that may provided a fast detection and accurate identification of the microorganism(s) in order to prevent the loss of life and minimize the extent of damage caused by harmful microorganisms. Additionally, there is a need to have better methods of air quality control and for communities to have a real sense of security in the current atmosphere of a highly probable potential for terrorist attacks.
Therefore, it is highly desirable to collect, detect and identify the bioaerosols or biological agents in a fast, efficient and accurate way.
There is a need for the quick and accuratel identification of those individuals that have been infected by a particular microorganism(s); in order to diagnose or detect human and animal diseases that can be identified by the host's exhalation of air in order to treat and reduce and/or totally control, if possible, the spread of the infection. Whereby, the possible attack or contamination source is neutralized or at least drastically reduced.